Repair-based semantics have been extensively studied as a means of obtaining meaningful answers to queries posed over inconsistent knowledge bases (KBs). While several works have considered how to exploit a priority relation between facts to select optimal repairs, the question of how to specify such preferences remains largely unaddressed. This motivates us to introduce a declarative rule-based framework for specifying and computing a priority relation between conflicting facts. As the expressed preferences may contain undesirable cycles, we consider the problem of determining when a set of preference rules always yields an acyclic relation, and we also explore a pragmatic approach that extracts an acyclic relation by applying various cycle removal techniques. Towards an end-to-end system for querying inconsistent KBs, we present a preliminary implementation and experimental evaluation of the framework, which employs answer set programming to evaluate the preference rules, apply the desired cycle resolution techniques to obtain a priority relation, and answer queries under prioritized-repair semantics.

翻译：基于修复的语义已被广泛研究，作为从不一致知识库（KBs）中获取有意义的查询答案的手段。虽然已有若干工作探讨了如何利用事实间的优先级关系来选择最优修复，但如何指定此类偏好的问题仍未得到充分解决。这促使我们引入一种声明式的基于规则的框架，用于指定和计算冲突事实间的优先级关系。由于所表达的偏好可能包含不良循环，我们考虑了如何判定一组偏好规则是否总能产生无环关系的问题，并探索了一种实用方法，通过应用多种循环消除技术来提取无环关系。为实现查询不一致知识库的端到端系统，我们提出了该框架的初步实现与实验评估，该框架采用答案集编程来评估偏好规则，应用所需的循环消解技术以获取优先级关系，并在优先修复语义下回答查询。